In 2014 I found a video on you tube of a man in Newfoundland who had built a solar pop can heater. I decided I would build one for my big shop in the back of my large town lot. There is a south facing wall to install it on a foot away from the wall for safety reasons as it can produce 80 -90 degree C!  I had an old double pane window in the shop that was about 3 by 7 feet. So the project began. I also had the aluminum frame from a score clock which had been removed from a school gym which turned out to be the perfect depth to fill with rows of pop cans after being insulated with 2 inch styrofoam. The metal frame also had a perfect indentation on the front to install the double pane window. See the pictures in the link below for how I  built  this pop can heater. I used a small squirrel cage fan on the inlet in the garage and another one on the outlet in the garage. There is a temperature sensor at the top of the outlet pipe connected to an adjustable digital temperature control ($8.00 on ebay). I can set any temperature to turn on the fans and I can also adjust the differential to turn off. As soon as the sun comes up and shines on the heater  it  will quickly come to the set temperature I programed of 32 C. The heater was tested to  produce up to +180 degrees F  (+80 degrees C) before I installed the fans. This is a good reason to have 2 fans so it will not melt the heater if one fan quits! Today Nov 11, 2020 the sun was very low (temperature – 12 degrees all day) but the heater quickly rose to +32 C and the thermostat turned the fans on. The heater produced a steady +18 C temp into the garage all day until there was no more sun shining on it. ! Darn nice free solar heat. 

Click the pictures in the gallery 

 

Click this link to see the picture gallery of this project